The present invention relates to microtome blades and, in particular, means for cooling such blades.
A microtome is a specialized machine utilized for cutting very thin sections, typically 2-15 microns in thickness, of plant or animal tissue for use in histology. Typically, the tissue has been embedded in a firm matrix of paraffin, celloidin, carbowax or similar material in order to facilitate cutting and to preserve the structural composition of the tissue. The sections cut are put onto slides, stained with dyes specific for particular structures, and viewed under a light microscope.
The histologic method used for cutting paraffin-embedded tissues is to put the tissue block on ice for several minutes, then attach it to the microtome and cut sections with the microtome blade at room temperature. However, it has been a regular practice in the cutting of certain tissues to cool the microtome blade in lieu of or in addition to cooling of the tissue block.
Several techniques have been used to effect cooling of the microtome blade. The simplest is holding an ice cube against the blade until it is cooled and then repeating this process as the temperature of the blade rises. This is, however, a very messy and inconvenient method because of the water from the melting ice cube.
Attempts have also been made to design various pieces of equipment to continuously cool the microtome blade. Such equipment is disclosed, for example, in "Effective Use And Proper Care of the Microtome", by Oscar W. Richards, Copyright 1959, pages 57-59. Such arrangements have, however, been short-lived and unsuccessful due to their excessive costs and to the intricacies of their design, frequently involving tanks of carbon dioxide, tubing, small motors and sometimes special knife blades designed for use only with that cooling equipment. Such prior art arrangements frequently limited the freedom of movment of the technician and thus had questionable merit.